2017: C1 cash costs $1.43 per pound
2018: C1 cash costs $1.93 per pound
2019: C1 cash costs $2.06 per pound:
C1 cash costs $2.21 for Q1 2019, $2.01 for Q2 2019, $2.05 for Q3 2019, and $2.01 for Q4 2019

Besides lower copper price, significant rising in C1 cash costs was the other main reason for poor financial performance and thus TKO share price.